Explosives and other controlled substances, such as drugs, have become major societal problems. Increasingly, terrorist acts using explosives are becoming a problem not only for countries in the Middle East but also for Western countries in other parts of the world. Explosives constitute a weapon used by terrorists and insurgents, wherein the explosives may be hidden in a myriad of devices; however, it is typically difficult for a person handling explosives to avoid contamination after coming into contact with an explosive or explosive device because explosives readily adhere to surfaces.
In addition to explosives, drug abuse has been a longstanding problem for Western countries and consumes large amounts of law enforcement resources each year. Canines, metal detectors, and “sniffer” detectors have been used at various locations, such as airports, border crossings, and the like to detect explosive devices and illegal drugs. These measures have had mixed success.
Another measure that has been employed to detect contraband substances has been to collect loose particles from surfaces or skin with a vacuum cleaner or a swipe. The swipe or the particles collected by the vacuum are then heated to release the vaporizable material for analysis. This approach is in routine use at airports throughout the world for screening airline passengers. An example of such a system is the Barringer™ Ion Scan System™; however, this technique has drawbacks. For example, the use of swipes or particle vacuums is an intermittent process, which requires manual intervention between the sampling and analysis. This is a time consuming approach that is inherently slow, although it may optionally be used in conjunction with at least one embodiment of the present invention.
Previously disclosed devices for volatilizing certain substances for detection include a high-energy apparatus disclosed in U.S. Pat. No. 6,895,804. The content of U.S. Pat. No. 6,895,804 is incorporated herein by reference in its entirety. The landmine detection apparatus of the '804 patent applies a relatively high amount of energy to the sample target that is generally intended to be soil. To provide the requisite energy, the radiation source of the '804 patent is powered by a relatively high amount of energy, and therefore, is limiting in its ability to serve as a self-contained backpack unit, handheld device, or other relatively compact portable device. In addition, high-energy strobes are slow to recharge, utilize kilowatts of energy to power, and are heavy as a self-contained unit that includes a power source.
U.S. Pat. No. 6,828,795, incorporated herein by reference, suggests use of an ion mobility spectrometer with a heat source, but energy levels have not been provided. U.S. Patent Application Publication No. 2005/0007119 A1, related to the '795 patent, is also incorporated herein by reference. The '795 patent discloses using an electrostatic precipitator to take out particulates, presumably to keep them out of the ion mobility spectrometer. It is noted here that, in at least one embodiment, the present invention advantageously releases a plume of particulates that is then able to form at least part of the signal.
As noted above, present techniques for airport security include sometimes screening baggage for trace explosives by manually swiping the surface of the baggage and analyzing the swipe, such as by using Ion Mobility Spectrometry. Not all bags are tested for trace explosives, with carry-on baggage typically being X-rayed but not always screened for traces of explosives. Thus, there would be an advantage to automatically screening all baggage, whether checked or carry-on, for explosives. In addition, upon arrival at a destination airport, government agencies at the destination airport typically also screen baggage, wherein such screen efforts typically include searches for drugs. Thus, it would be advantageous to be able to automatically screen baggage upon arrival, such as when baggage is unloaded from international flights. Accordingly, among other types of screening uses, such as crime scene analysis, there is clearly a need for automatically screening airline baggage and carry-on items for traces of explosives and drugs.